RFR: 8320725: C2: Add "requires_strict_order" flag for floating-point add-reduction [v8]

[Bhavana Kilambi]

On Mon, 13 May 2024 11:01:30 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> @eme64 Thanks for the clarification. I understand the usage of `counts` in the IR tests. Just that I got a bit confused by some of your earlier statements. We do actually have a test to make sure AddReductionVF/VD and MulReductionVF/VD are not generated on aarch64 NEON machines - `test/hotspot/jtreg/compiler/c2/irTests/TestDisableAutoVectOpcodes.java`. I can modify this test to include UseSVE > 0 case as well and will also add a separate JTREG test for the VectorAPI tests. Hope that's ok..
>
> @Bhavana-Kilambi
> I know we have the tests in `test/hotspot/jtreg/compiler/c2/irTests/TestDisableAutoVectOpcodes.java`, and some other reduction tests. But these do not do the specific think I would like to see.
> 
> I would like this:
> - Add `no_strict_order` vs `requires_strict_order` or similar to `dump_spec`.
> - IR match not just that there is the correct `ReductionNode`, but also that it has the `no_strict_order` or `requires_strict_order` in its dump. You can do that by using a custom regex string, rather than `IRNode.STORE_VECTOR` or similar.
> - Then, create different tests, some where we expect ordered, some unordered vectors. Use Vector API and SuperWord examples.
> 
> Does that make sense?

Hi @eme64 , I have added the dump_spec as suggested and also two JTREG IR tests for superword and vectorapi. I have not modified the existing tests for superword and created a separate test instead as it might be easier to extend these tests for other platforms in the future if needed. Thanks for your suggestions. Please do review and let me know if any changes are required.

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PR Comment: https://git.openjdk.org/jdk/pull/18034#issuecomment-2114782520